Plants, Organisation and Diseases Flashcards
Give the seven signs of plant disease
Stunted Growth, Spots, Decay, Growths, Malformed Stems and Leaves, Discolouration, Pests
Four tests for plant disease identification?
Google or Gardening Manual, DNA Analysis, Monoclonal Antibody Testing Kits, Lab Identification
What pathogen causes rose black spot?
Fungus
What pathogen causes tobacco mosaic virus
Virus
What causes nitrate deficiency (clue in the name)?
Lack of nitrates
What causes magnesium ion deficiency?
Lack of magnesium
What are the three types of plant defence adaptations?
Physical, Chemical, Mechanical
Give three physical defences
Layers of dead cells around the stems (bark), tough waxy cuticle on leaves, cellulose cell walls.
Give two chemical defences
Poisons and Antibacterial Chemicals
Give three mechanical defences
Leaves that curl or droop when touched, thorns and hairs, mimicry.
Give all parts of a plant cell
Nucleus, Chloroplasts, Vacuole, Mitochondria, Cell Wall, Cell Membrane
What parts in a plant cell are not in an animal cell?
Vacuole, Chloroplasts, Cell Wall
Name the organs in a plant
Stem, roots and leaves
Name the parts in a leaf (top to the bottom)
Waxy cuticle, upper epidermis, palisade mesophyll, spongy mesophyll (contains air space), lower epidermis, stomata, guard cell
Function of epidermal tissues
Covered in waxy cuticle to reduce water loss via evaporation
Function of upper epidermis
Transparent so light can pass through to the palisade layer
Function of palisade layer
Contains lots of chloroplasts containing chlorophyll for photosynthesis so the palisade layer is near the top of the leaf to maximise light intake
Spongy mesophyll function
Contains air spaces to increase the rate of diffusion of gases by decreasing the diffusion pathway
Stomata, guard cells and lower epidermis
Lower epidermis is full of stomata which open and close to allow gas exchange and are controlled by guard cells in response to the environment
Translocation
The movement of food substances (mainly sugars) in cell sap forwards and backwards along the plant
How are phloem tubes specialised?
Made of columns of elongated living cells with small pores in the end walls to allow for sap to flow through
Translocation
Transportation of water and minerals from the roots to the stem and leaves in one direction
How are xylem specialised
Made of dead cells joined end to end with no end walls between them and a hole down the middle, they are strengthened with a material called lignin
Transpiration stream
The movement of water from the roots through the xylem and out of the leaves is called the transpiration stream
What is transpiration?
Evaporation and diffusion of water from a plant’s surface mainly the leaves’ surface
Factors affecting the rate of transpiration
Light- brighter means greater rate, temperature- warmer means greater rate, air flow- water particles are attracted to each other so air making water vapour move away from plant means greater rate, humidity- the less humid the bigger the diffusion gradient so the greater the rate
How are the stomata specialised
When a plant has a lot of water, guard cells fill with it which makes the stomata open so gases can be exchanged for photosynthesis- when the plant has less water the stomata close to prevent loss of evaporating water- they are sensitive to light and close at night to save water- they are on the bottom because it is cooler so less water is lost
